Volume2,March 2015,

Abstract:MANETs has been experiencing exponential growth in the past decade. Due to their vulnerability to various attack makes extremely prominent for its distributed and independent nature. Among these various DOS attacks black hole, grey hole, and co-operative black hole attack may collapse the network, and this may become a major threat in MANETs. Here we are using Dempster-Shafer evidence based theory to collect various evidences for various nodes in the network against black hole and grey hole attack. For detecting malicious node we used Direct Trust Value (DTV) to detect a single black hole attack. DTV is calculated for each node that exists in the network and then that value is compared against predetermined threshold, if the calculated value is less then predetermined threshold then the node is malicious node..